Tripoli, Libya (CNN) -- Libya's embattled government accused rebels and the NATO military alliance of carrying out a coordinated air, sea, and land attack on the strategic oil town of Brega on Thursday, the same day a government spokesman vowed to "die for oil."

In an unexpected late-night appearance before a hastily assembled group of journalists, a Libyan government spokesman called the attack "heavy, merciless and surprising."

CNN was not able to reach anyone from NATO or the Transitional National Council, based out of the opposition-held eastern Libyan city of Benghazi, to confirm reports of the Brega attack.

The government spokesman, Musa Ibrahim, also issued a warning that he said he hoped would make headlines around the world. "We will die for oil. We will kill for oil," Ibrahim said. "We will kill everyone who comes near our oil. Rebels, NATO, we don't care. We will defend our oil to the last drop of blood that we have."

His comments came shortly after Gadhafi used similar imagery in pledging not to knuckle under to international demands that he cede the power he has held tightly for nearly 42 years, and instead said he would remain "until the last drop of my blood."

"It is impossible for me to leave my loyal people," he told an enthusiastic crowd numbering in the thousands in the western city of Ageelat, in a speech that was broadcast over state television.

"I will remain with my people and with my firearm until the last drop of my blood. We will win over this unjust campaign. We will win over the campaign of colonization, the campaign of hatred."

After Gadhafi spoke, dozens of young men dressed in civilian clothes and carrying shiny new Kalashnikov rifles in a crowded square fired their weapons into the air in celebration.

One of the participants in the pro-government demonstration said he had a message for Libyan rebels who have been fighting Gadhafi's forces on three fronts: "I would tell our brothers in Misrata and Benghazi, stop the bloodshed," said Walid Khaila, a 22-year old medical student.

Libya has been riven by a civil war since shortly after peaceful anti-government protests in February were met by violent crackdowns by government forces. That prompted NATO forces in March to launch a campaign of airstrikes against government troops and command-and-control centers, as well as the Libyan leader's compound in Tripoli.

Gadhafi said he would welcome warm relations with Europeans, who compose many of the NATO forces. "We want a strong relationship, cooperation and peace with the European people, and not with the war criminals, who must leave immediately," he said.

He added, though, that he and his followers are prepared to endure privation to ensure he remains the leader of Libya. "We are ready to live without electricity, without benzene, without buildings, and without air conditioning," he said. "But our firearms are in our hands to fight until the end."

Their statements came on the same day that Libya's prime minister warned Western governments they were looking at their last opportunity to engage in oil deals with Tripoli.

"Now is the last chance for any nation contributing to the aggression to review their policy," Baghdadi al-Mahmoudi said after meeting with top Libyan oil industry executives. He said any future oil deals with Italy and its energy giant ENI were already off the table. Rome and Tripoli were close trading partners until the conflict erupted in Libya last winter. Tripoli has said that ENI alone invested tens of billions of dollars in Libya's oil and natural gas industry.

Italy scrapped a friendship treaty with Libya last February, in the wake of Colonel Moammar Gadhafi's bloody crackdown on peaceful opposition demonstrators. Later, Italy joined the NATO bombing campaign of Gadhafi's forces, after the United Nations Security Council passed two resolutions authorizing the use of force to protect Libyan civilians.

Also Thursday, the United Nations reported it completed a four-day humanitarian assessment mission to the port city of Misrata, site of intense fighting in recent months. Though aspects of normalcy have returned to the city, it remains surrounded by government forces and exposed to intermittent rocket attacks, the world body said in a release.

Misrata is 210 kilometers (130 miles) east of Tripoli on the Mediterranean and, because of the government forces around it, can be reached only by sea.

Though some shops and markets have reopened, rising food prices, a shortage of supplies and a lack of cash mean that most residents have been short of food.

The World Food Programme said that, since April, it has distributed 2,634 metric tons of food in Misrata to 125,000 people.